1. Field of the Invention
The invention relates to an electrophoresis device, an electrophoresis method using an electrophoresis device and the use of the electrophoresis device.
2. Description of Related Art
Electrophoresis devices and electrophoretic separation methods are known in which sample substances are fractionated, at the interface between the liquid phase and the solid phase, into the individual sample species.
An analogous separation method, namely pressure filtration, has already been used in industry on a broad scale and is widely used to separate biopolymers. In comparison, electrophoretic separation, i.e., the so-called electrophoretic filtration process or, in short, electrofiltration is used rarely on the whole, although this process appears to be particularly advantageous. In contrast to pressure filtration, it is not the entire sample volume but only the ionic species and not the entire volume of the solvent which need to be transported during the electrophoretic transfer via the separation membrane provided in the separation chambers of the corresponding electrophoresis device. The reason for the rare application of the electrofiltration process is based on the fact that problems occur in particular during the separation of biopolymers according to this process. These problems appear to reside, inter alia, in the irreversible sorption and denaturisation of the biopolymers. The restriction imposed on electrofiltration by technical problems in the optimum dissipation of the heat, which arises during the electrophoretic process and in the changes in the separation characteristics of the material of the solid phase, i.e., the separation membrane.
Irreversible sorption at the interface between the liquid phase and the solid phase, i.e., the separation membrane, can be largely minimized by using biocompatible synthetic resin membranes. However, it has so far not been possible to prevent the change in the separating characteristics of the membrane after a prolonged period of contact with the biopolymers to be separated, which is referred to as “fouling.”
The problems which occur during the use of electrofiltration as a result of the heat development inherent in this separation process decisively restrict, in practice, both the application range of this process and the quantitative throughput in comparison with pressure filtration. In the case of an unfavourable increased development of heat in the material of the separation membrane, the characteristic separation properties can be significantly altered and, as a result, the material can even be destroyed as a result of overheating.
Moreover, electrophoretic separation methods for separating bioparticles in aqueous solution, which are referred to as carrierless electrophoresis or free flow electrophoresis (FFE), and corresponding electrophoretic separation devices are known. During this electrophoretic separation of bioparticles in aqueous solution, media with a high conductivity need to be used in order to maintain the vitality of the bioparticles during and after separation. For this purpose, it is necessary inter alia to solve the problem of the optimum removal of heat from the separation chamber since rising temperatures in the separation chamber cause a substantial deterioration in the separation performance. This means that, for an optimization to be achieved, the temperature gradients at every point in the separation chamber gap as well as the temperature differences at the different points in the separation space need to be minimized. In order to improve the separation performance of FFE, the separation of the bioparticles must also take place with the electrical field strengths being as high as possible which, as a result of the high conductivity of the media, leads to a more than proportional increase in the process heat evolved during the separation process.
The electrophoresis devices available on the market for separating bioparticles, which operate according to the FFE process, have therefore been optimized insofar as, on the one hand, an electrical field strength necessary for the desired separation performance was used and, simultaneously, an optimum elimination of the process heat was achieved by selecting as small a separation chamber gap as possible. In European Patent EP 0 443 024 B1, an electrophoresis device with longitudinal hollow fibres is used to pass through a cooling medium.